Recovery of sulphur



' of an improved catalyst Patented July 11, 1933 UNITED STATES PATENT OFFICE MNNETH M. BA'UM, OF CLABKDALE, ARIZONA, ASSIGNOR T UNITED VERDE COPPER COMPANY, OF CLARK'DALE, ARIZONA, A CORYORATION OF DELAWARE RECOVERY OF SULPHUR Re brewing.

combined sulphur.- More particularly, the

invention contemplates the provision of an improved process for recovering sulphur from gaseous sulphur compounds. The invention further contem lates the provision or promoting chemical reactions.

l have discovered-that chemical reactions may be accelerated appreciably when coni is the better adsorbent for another of the reagents. Thus, for example, I have discovered that in carrying out a reaction between sulphur dioxide and hydrogen sulphide for the production oi elemental sulphur, the reaction is accelerated it carried out in the resence of a mixture of activated carbon w hich adsorbs hydrogen sulphide more readily than it adsorbs sulphur dioxide and a mineral gel such, for example, as an artificial zeolite or silica gel which adsorbs sulphur dioxide more readily than it adsorbs hydrogen sulphide.

In preparing catalysts in accordance with the present invention, it is advisable to form an intimate mixture of the components. The production of intimate mixtures will be tacilitated it one of the initial components is a normally solid orous substance and another is a fluid which may enter the pores of the solid. it one of the components is liable to be consumed or destroyed by one or more of the reagents or by another substance contained in the reaction mixture, it is advisable to so form the mixture that that component is impregnated and/or coated with the other Application filed September 25, 1929. Serial No. 395,178.

before the mixing of the components takes place, or if the carbon is mixed with the artificial zeolite mixture or the silica gel mixture before the gel forms, the gel will be formed or deposite on the surfaces and in the pores of the carbon particles, and the coated or impregnated carbon particles may be utilized 1n promoting a reaction between hydrogen sulphide and sulphur dioxide whether or not free oxygen is resent in the reaction mixture and without t e carbon being consumed or destroyed when free oxygen is present.

In preparing catalytic agents in accordance with my inventiori, I prefer to use car bon which has been produced and activated by distilling wood, coal or lignite, at a low temperature, preferably below 600 (1, until substantially all of the volatile matter has been removed and treating the charcoal thus formed with live steam or air.

In preparing a mixture of activated carbon and a mineral gel, 1 may first mix finely divided carbon with a solution of one of the components of the gel and then add the other component and permit the mixture to gel. After the gel has formed, the composite agent is washed and dried at a low temperature, and, when dry, it is granulated to provide particles of the desired sizes.

. In order to insure the presence of gel in the pores of the carbon particles, it is sometimes desirable to first mix the components of the gel to form a mixture of such fluidity that it may easily enter the pores of the carbon particles and then incorporate the carbon in the mixture before the gel forms. It is also desirable to form the composite agents under reduced pressures in order to remove air and other gases from the pores of the carbon particles and permit the gel components to enter readily.

Mixtures of carbon and mineral gels may also be formed in accordance with the present invention by mixing finely divided carbon and gels and compressing and subse uently granulating the resulting mixtures. arbon may be deposited as a reaction product in the pores of a mineral gel to produce a composite catalyst.

When the composite agent is formed by bon should be such that a bed of the composite agent will permit fluid penetration. I have found'that carbon particles'rangi in size between and 20 mesh may be use advantageously.

Carbon may be used in any desired proporcoat and/or impregnate the carbon particles. I have found that composite agents containing about two parts by weight of carbon and one part by weight of gel are highly satisfactory.

In utilizing a composite catalytic agent of my invention, for example, in the production of elemental sulphur from hydrogen sulphide and sulphur dioxide, the h drogen sulphide and S111 hur dioxide may e obtained from any deslred sources. In view of the fact that the carbon contained in the compjosite reagent will not be consumed apprecia ly in the eventthat; free oxygen is present, it is not essential that oxygen-free gases be used. Sulphur dioxide gases produced during the smelting of sulphide ores, and hydrogen sulphidewhich may be obtained fromthe interaction of acids with mattes obtained during the same operations provide suitable raw materials. I

The granulated composite catalyst is formed'into porous beds in suitably enclosed 4o chamber and a mixture of the two gases is passed through such beds, preferably through two such beds in series. The reaction is initiated at atmospheric temperatures and proceeds according to the following equation:

Sufficient heat is developed to vaporize all water formed. The elemental sulphur is deposited on the catalyst and the activit of thecatalyst is gradually impaired. V hen the activity of the catalyst has been impaired to such-'an extent that the s gel. 2. The method of recovering sulphur which tions, but, in order to ,obtain the best results,- suificient gel should be present to thoroughly tween hydrogen sulphide and-sulphur dioxide peed of the rethe action of sulphur dioxide in the presence of particles of activated carbon impregnated with an artificial zeolite.

5. An agent for promoting a reaction between hydrogen sulphide and sulphur dioxide comprising a mixture of activated carbon and an artificial zeolite.

6. An agent for promoting a reaction be-' comprising particles of activated carbon impregnated with an artificial zeolite.

7. The method of recovering sulphur which comprises subjecting sulphur dioxide to the action of a reducing agent in the presence of a mixture of activated carbon and a mineral ge 8. The method of recovering sulphur which comprises subjecting hydrogen sulphide to the action of an oxidizing agent in the presence of a mixture of activated carbon and a mineral gel.

9. The method of recovering sulphur which comprises subjecting hydrogen sulphide to the action of sulphur dioxide in the presenceof a mixture of adsorbent materials one of which is the better adsorbent for hydrogen sulphide and another of which is the better adsorbent for sulphur dioxide.

10. The method of recovering sulphur which comprises subjecting sulphur dioxide to the action of a reducing agent in the presence of a mixture of adsorbent materials one of which is a zeolite.

11. The method of recovering sulphur which comprises subjecting hydrogen sulphide to the action of an oxidizing agent in the presence of a mixture of adsorbent materials one of which is a zeolite.

12. The method of recovering sulphur which comprises subjecting sulphur dioxide to the action of a reducing agent in the presence of a mixture of adsorbent materials one of which is activated carbon.

. 13. The method of recovering sulphur which. comprises subjecting hydrogen sulphide to -the action of an oxidizing agent in the presence of a mixture of adsorbent materials one of which is activated-carbon.

In testimony whereof I aifix my s' ature.

KENNETH M. B UM. 

